Stuart D. Gathman wrote:
I'm not convinced that a label with no dot is a FQDN.
I'll have to look up the definition.
You really think TLDs are no FQDNs ? The best explanation
I know (and for that reason also an informative reference
in RFC 4408) is http://tools.ietf.org/html/rfc3696#section-2
| Consequently, purported DNS names to be used in applications
| and to locate resources generally must contain at least one
| period (".") character. Those that do not are either invalid
| or require the application to supply additional information.
| Of course, this principle does not apply when the purpose of
| the application is to process or query TLD names themselves.
Better read the complete section, it's rather interesting,
with historical explanations, good and bad heuristics, and
why hardwiring lists of TLDs into applications won't work
anymore.
I've seen a lot of code that tests for FQDN by testing for a
dot. Perhaps all that code is wrong. Perhaps not.
For SMTP as specified in 2821 and the (01) 2821bis draft it's
fine. SMTP intentinally doesn't support TLDs, because it tries
to get rid of "bare labels", as that used to be the name of a
host _without_ the labels to get a fully qualified domain.
Applications tried some black magic, adding ".domain.example"
on the fly for a host "test" to get FQDN test.domain.example.
For obvious reasons that magic didn't always work as expected,
and therefore "plan B" was to disqualify it as syntax error
in ESMTP. And also in the <domain-spec> of SPF, or in USEFOR,
for this and other reasons. IIRC we needed it in SPF only to
eliminate an ABNF ambiguity.
Otherwise, no compatibility issues, TLDs are domains like any
other domain, and the spec. doesn't say that <target-name> has
to have at least one dot.
But I think the spec. forgot to mention that a trailing dot
has to be removed for the purpose of "macro expansion". I'll
add this to the errata: The meaning of a:%{h}%{h] should not
depend on the presence or absence of a trailing dot in HELO
(just an example, other macros are also affected).
For something like MAIL FROM:<"dot."@example> and %{l} screw
it, it's too rare to be taken seriously. Or should any "dot-
pruning" be limited to h, d, o ?
Frank
-------
Sender Policy Framework: http://www.openspf.org/
Archives at http://archives.listbox.com/spf-discuss/current/
To unsubscribe, change your address, or temporarily deactivate your
subscription,
please go to http://v2.listbox.com/member/?list_id=735